This invention relates to an electronic sphygmomanometer having recording means for producing a hard copy of measured blood pressure.
In a conventional electronic sphygmomanometer, measured blood pressure is displayed or recorded by a liquid-crystal display unit or recording means such as a printer each time a measurement is completed. However, merely displaying or recording the numerical values of systolic and diastolic blood pressure on a measurement-by-measurement basis does not enable one to fully comprehend the variation which these values undergo. More specifically, blood pressure is a constantly varying quantity by nature and one cannot tell from a mere single measured value thereof whether that value is an ordinary blood pressure for the individual. Moreover, since blood pressure varies depending upon the individual's mental and physical state and the external surroundings at the time of measurement, one cannot tell from the results of only a single measurement whether the individual's blood pressure is truly abnormal. Accordingly, in order to correctly grasp the meaning of a measured value of blood pressure, it is important to accumulate the results of measurements taken a number of times every several hours or every other day and observe the variation in these blood pressure values.
Thus, observing the change in blood pressure values is vital in terms of controlling an individual's blood pressure. For this reason, the written operating instructions provided with electronic sphygmomanometers are almost always accompanied by special recording note paper for the purpose of recording measured blood pressure values. However, writing down the results of each and every measurement is a very troublesome task so that the user eventually tires of the task of continuously writing down the measured values. It is doubtful whether correct diagnosis of the patient's condition can be made in such a situation.
Temperature, humidity and the temperature-humidity index are some of the environmental factors that are intimately related to changes in blood pressure. Among these factors, temperature is especially critical. In general, the lower the atmospheric temperature, the higher blood pressure tends to become. However, temperature and other environmental information that has an influence on blood pressure cannot be measured and recorded with the conventional electronic sphygmomanometers.
In other electronic sphygmomanometers, all that is done is to provide a numerical display of a measured blood pressure value on a liquid-crystal display unit or a printed indication of the measured value by means of a printer at the completion of each measurement. In consequence, measured values of systolic and diastolic blood pressure cannot be compared with an appropriate blood pressure to enable the relationship between them to be readily understood. The state of the art is such that the relationship can only be understood after first being subjected to processing.